This shouldn’t be hard to figure out given how few people were in the meeting with the Russian lawyer and part of the email chain. But it is hard to figure out because no one involved had an obvious motive to leak and those with an obvious motive weren’t involved.

Those with an obvious motive who weren’t involved: The name that keeps coming up in Twitter speculation is Mike Pence, who gets a little closer to the presidency every time another Russiagate shoe drops. But Pence wasn’t in the meeting or on the email exchange. For good reason — he wasn’t named VP nominee until mid-July, weeks after the meeting took place in early June.

Statement from @VPPressSec on Donald Trump Jr meeting and @VP's knowledge pic.twitter.com/iYiyoWfHRx

— Kasie Hunt (@kasie) July 11, 2017

Even if Pence were willing to drop a dime on Don Jr, a fantastically risky move given that it would pit him against the Trump family, how would he have gotten hold of the emails?

Another possibility: Some disgruntled outside advisor, like Corey Lewandowski or Roger Stone. How would Lewandowski or Stone have gotten hold of the emails, though? And why would they want to wreck the Trumps by leaking something as damaging as this to the Times? Even if they’re annoyed at not being given White House jobs, their proximity to Trump remains their meal ticket. Getting caught hanging the president’s son out to dry would render them persona non grata with Trump himself and might even inspire a nasty revenge operation. They just don’t gain enough to risk that.

Yet another possibility: Someone hacked the emails of one of the people on the email chain and handed them to the Times. Maybe it was a freelance hacker, maybe it was a foreign government’s intelligence unit. Maybe it was the Russian government’s intelligence unit, turning up the heat on Trump over his standoffishness in rolling back sanctions. (If you think Russiagate is bad now, imagine a scenario where the Kremlin is blackmailing the White House with periodic hangouts of damaging stuff.) Here’s an … interesting tweet:

Contacted Trump Jr this morning on why he should publish his emails (i.e with us). Two hours later, does it himself: https://t.co/FzCttGSyr6

— Defend Assange Campaign (@DefendAssange) July 11, 2017

The problem is, the Times gave us a clue about its sources in one of the previous Don Jr stories of the last few days. It was “three advisers to the White House briefed on the meeting and two others with knowledge of it” who first told the Times that the purpose of the meeting wasn’t to discuss Russian adoptions but to relay dirt on Clinton. In all likelihood, one or more of those same sources provided the emails.

Those who were involved but had no motive: Neither Don Jr nor Rob Goldstone have any reason to want a major paper to know they were party to an effort to receive dirt on Hillary Clinton from the Russian government. Manafort and Jared Kushner arguably do have a motive, as each recently had to disclose the meeting to the feds,
Kushner as a condition of his security clearance and Manafort to federal investigators probing the Russia matter. Leaking to the Times that it was Don Jr who organized the meeting with a Russian, not them, makes their own attendance seem a bit less damning. (Manafort is claiming that he never saw the “Russian government” part of the email chain since he didn’t read down that far. As if Paul farking Manafort, former Yanukovych lackey, would have some strong ethical objection to meeting with a Russian official.) But what motive does each man have to specify that the meeting was about collusion, specifically? It may have been Don Jr’s show but they were still in the room. Politico:

“Extremely damaging,” said former Justice Department prosecutor Peter Zeidenberg [of the emails]. “Certainly shows an intent to collude with Russian government.”…

“I think he’s walked himself into a potential criminal offense here,” [a Washington white-collar defense] lawyer said. But the disclosures could also be trouble for Kushner and Manafort since they are copied on the exchange and Trump Jr. at one point explains he’ll be bringing them along to the meeting at Trump Tower.

“They’re in the soup too,” the attorney said.

A possibility: In disclosing the fact to the feds that this meeting happened, either Manafort or Kushner was forced to also disclose what the meeting was about. As soon as they did, they began to panic that the feds would leak it themselves and suddenly they’d be in the midst of an enormous media clusterfark in which it would seem they were willing participants in a meeting aimed at colluding with a representative of the Russian government against Hillary Clinton. So instead the leaker or his allies decided to get ahead of the story and to leak it himself, putting himself in the best possible light — it was Don Jr who arranged the whole thing, neither Manafort nor Kushner knew what the meeting was about ahead of time, etc. It’s the same tactic Don Jr himself used this morning, posting the unflattering email chain knowing that the Times was about to publish it. It’s a way to signal, however unconvincingly, that you feel you’ve done nothing wrong. Maybe Jared or Manafort suspected similarly that their disclosure to the feds about the meeting would end up in the Times anyway and they chose to take control of the narrative by pushing it out there themselves.

If that’s the case, though, riddle me this: Why wasn’t the Times’s previous story about the meeting more flattering to the leaker? At one point it’s mentioned that either Manafort or Kushner left the meeting after 10 minutes, further exculpating the man who left. But the Times never says which one it was. Natalia Veselnitskaya, the Russian lawyer, clarified that in today’s interview with NBC:

“I could recognize the young gentleman who was only present in the meeting for probably the first seven to 10 minutes, and then he stood up and left the room,” she said. “It was Mr. Jared Kushner. And he never came back, by the way.

“And the other individual who was in the same meeting, but all the time he was looking at his phone. He was reading something. He never took any active part in the conversation. That was Mr. Manafort.” Midway in the interview, she described Manafort as “absent-minded.”

Kushner left, Manafort was disengaged. Assuming one of them was the leaker, why didn’t they emphasize that in talking to the Times’s reporters? Was it because the leaker feared that a too-flattering portrayal of his own actions that day in the story would be a tipoff that he had fed it to the paper?

Exit question: What does Congress know and when did they know it?

"Another shoe just dropped, as I told you weeks ago. More shoes will drop."
–John McCain on the Trump JR. emails

— James Arkin (@JamesArkin) July 11, 2017

Update: Speaking of Lewandowski and Stone, between whom there’s no love lost, Stone thinks the leaker is — surprise — Lewandowski:

Although there’s no evidence to support the theory, [Stone and Sam Nunberg] settled on former Trump campaign manager Corey Lewandowksi, whom they clashed with during the campaign, as a likely suspect. Lewandowski was fired from the campaign by Trump’s adult children the same month as the meeting, with Trump Jr. playing a key role.

“Donny was a vocal critic of Corey, he walked him towards the exits, and fits the broad definition of a White House advisor,” Stone said. “I’m not unbiased, but he’d be my choice.”